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ANDERSON COOPER, CNN ANCHOR: Good evening, everyone. 8:00 p.m. here in New York, 8:00 a.m., day 50 in the flight 370 search area. There is breaking news in the current loop and sonar mission ending. We got late word on where the target area is now expected to move.

In addition, new theories tonight about what actually happened, sharp reaction t mix messages from authorities, people demanding to know more over being told. They will have to wait even longer for. We got all the angles ahead.

Also tonight, take a look. This is happening to more and more children, rare childhood diseases, preventable ones that could do far worse than just raise a rash when the nasty one is making a comeback. We will tell you where and talk to our Dr. Sanjay Gupta about it.

We begin tonight with breaking news at a crucial phase in the search for flight 370. That single Bluefin-21 sonar scanner has now covered about 95 percent of the area the investigators have polling the likely as possible resting place for the missing Boeing 777. When it is done, and if now wreckages found, we're just now learning where the next focus area might be.

Remember, Bluefins have been on more than a dozen missions over the last week and has yet to find anything. We have yet to see anything, not one single image from the robot sub. Seven weeks ago, in the overnight hours, flight 370 took off with 239 people on board. And a part from sketchy radar reflections, several satellite connections and a handful of possible sonar pings, there has been no signs of the airliner.

While most experts believe the plane will be located and the answers will come. This is for now the longest running aviation mystery of our time. Tonight, we'll look at some of the new approaches that investigators you may need to try in order to crack it.

First though, Miguel Marquez in Perth, Australia with the breaking news.

So, the Bluefin has nearly completed the first phase of the search homing over the entire area that was focused around the strongest ping they detected. What is the latest, any sign?

MIGUEL MARQUES, CNN CORRESPONDENT: No sign of the plane. And at this point it is probably very likely that the Bluefin has completed that mission 13 and probably covered 100 percent of the area. What the -- authorities here are saying now is that they will continue to search the adjacent areas with Bluefin to that pinger number one location to see if there is anything they can pick up around it. And then as we understand they will pick everything up and move six miles north at some point. Whether they can do that with the Bluefin or some other technology that they will have to employ is yet to be seen, Anderson.

COOPER: And moving north because that is where another ping had been heard, correct?

MARQUEZ: This was the first ping that was heard. It was a very long sort of ping. A very good quality. They got four in total. Two of them were not so great. Two of them were very good. They started with the best, strongest signal. They're going now to the second best strongest signal. It could be somewhere in between those two. But this is the best that they have right now. Of and it is hoped that it will be found somewhere around that first ping, Anderson?

COOPER: All right, Miguel Marquez, thanks.

Can't be said enough for anyone with ties in the missing 2539 passengers and crew members. It is not an aviation mystery or the logistical puzzle. It is the fate of a father or a daughter, a life partner, friend. That's why week after week, those lost love one or flight go the demanding more and better information from authorities, especially from Malaysia authorities. Indeed, they say are getting a steady does of aviation and mixed message.

Yesterday, CNN aviation correspondent Richard Quest took their search for answers right for the top, sitting down with Malaysia's prime minister. And some argue they will get the same. Here is an example.

(BEGIN VIDEO CLIP)

RICHARD QUEST, CNN AVIATION CORRESPONDENT: Prime minister, are you prepared to say that the plane and its passengers are lost?

NAJIB RAZAK, MALAYSIAN PRIME MINISTER: At some point in time I would be. But right now I think I need to take into consideration the feelings of the next of kin. And some say they're not willing to accept it until they find hard evidence.

(END VIDEO CLIP)

COOPER: Well, that was yesterday. A month ago he said the opposite. Listen.

(BEGIN VIDEO CLIP)

NAJIB: It is therefore with deep sadness and regret know -- that I must inform you according to this new data, MH-370 ended in the Southern Indian Ocean.

(END VIDEO CLIP)

COOPER: Joining us now is Steve Wang whose mother was aboard flight 370. Steve, thanks for being with us. I am sorry it is under those circumstances. I can only imagine how frustrated you are at this point. How are you holding up?

COOPER: You have been searching for answers, getting none from Malaysian officials. Our reporter, Richard Quest in Kuala Lumpur, he asked the prime minister about frustration of the families and I want to play for you what the prime minister said. Let's listen.

(BEGIN VIDEO CLIP)

NAJIB: I know this is a very, very excruciatingly painful time for the family members, I understand that. And we did our best. We did many, many briefings and we gave them as much information as we could in terms of information that could be -- that was corroborated. But the most important information that they want and sadly the one that we cannot provide is where is the plane?

(END VIDEO CLIP)

COOPER: Do you accept that answer?

WANG: Well, it tells me nothing. We are asking technical questions and this Monday in Kuala Lumpur in Beijing. We were asking questions about Inmarsat. But they never gave such kind of information to us. And what we asked for, there was records from the tower and the plane. They didn't provide. We asked about radar, they didn't provide it. I don't know what kind of information, they have already provided it to us.

And you know, what we want to do is to ask for Inmarsat to help us confirm whether they are searching the right place or not. And it is very -- unfortunately, they, the militia government, it is messed up, asking technical questions, not facing the fact.

You know, we are asking questions to help them find the plane. But they said stop it and move on to the next step. They act as though they have some certification or something like that, that is really terrible for the family members.

COOPER: I mean, I saw the list of questions and a lot of them are very good rational questions about, you know, the electronic locater transmitters about what kind of box they're stored in. I mean, they're very technical questions. I was stunned to realized that the family members, at the very least, had not been given those answers up to this point. I mean, those are answers that could easily be given to family members.

WANG: Yes, so that is the point. We asked only technical questions. It is not about MH-370. But it is about the plane, 777. About the system, how it works. But they still refused to give us the answer. I don't know what kind of good communications that they are providing to the family members.

COOPER: Are you prepared -- I mean, this point it has been seven weeks. Are you prepared for the possibility they may never find this plane? Or are you convinced they will find this? It is just a question of how long?

WANG: Well, with the high tech technology, I think I am very confident that the plane will be found. But it will take a long time, but it will finally be found.

COOPER: Steve Wang, I'm so sorry that all you're going through. And my best to your family. Thank you.

WANG: Thanks.

COOPER: And turning to the panelists, CNN aviation analyst David Soucie, author of "Why planes crash: an accident investigation flights for safe skies," also analyst David Gallo, director of special projects of Wood Hole Oceanographic Institution, he co-led search for Air France flight 4447, and aviation correspondent Richard Quest, who got that exclusive interview with Malaysia's prime minister.

Richard, clearly, the families are understandably frustrated. What has been the reaction to your interview? Were you -- I mean, you were able to get the prime minister to promise to release the investigation's preliminary report. But it is really no secret that the government there is not used to that kind of transparency.

QUEST: I think the reaction from the families was in some ways predictable. They don't believe the prime minister will keep good on his promise. And even if he does release the report they are still convinced that something will be left out. Something will be hidden.

The families really fall into several categories and we really can't lump them all into one group. There were those who in some ways have come to terms with it. They have a dignified silence and they are looking forward to the next or they are getting ready to move on to the next part of the process.

There are those who want answers, what actually happened and what can the government and what airline tell us? And then there are those who simply believe the plane is waiting to be found. Diego Garcia, Kandahar, wherever you like.

So, an entire range of family reaction which basically all comes down to the same view that they still don't believe the government is providing sufficient information.

COOPER: And David Soucie, we now hearing the search area is expected to shift nor to that area around the first ping, you say you though all along, this should have been the focused, why?

DAVID SOUCIE, CNN SAFETY ANALYST: Well, simply because it had a longer period of sustained ping reception. And to me that would give them much more information. But I suspect that through a couple of sources I talked to that that area is much deeper. So I think they kind of worked under where they thought they could work. And it was a good chance. It was in the center of all pings where they started. But I think that they're going to have much better luck once they get deeper equipment where it could work and go up to the first ping.

COOPER: And David Gallo, I mean, had the search so far, I mean, that it obviously it seems as it turned up nothing. Has it been a waste of time or is that a fair criticism?

DAVID GALLO, CNN ANALYST: I don't know, Anderson. I don't think it has been a waste of time because knowing where the plane is not. That is important information too. And as long as they're confident that they have not missed it, that is up to the search team and the analysts to decide. So the next bit is problematic because if they go too far to the north, it is going to get rapidly deeper and much more rugged. So that -- it will involved a whole new set of technology.

COOPER: And I mean, David Gallo, can we be confident when they say they found nothing using the Bluefin that there is no chance it missed something?

GALLO: You know, they have been going low and slow, just that if there is anything there that is not natural that it would pop up on that screen. But that is all going to depend on the abilities of the operators. And that is a tried and true team. So I think that they have that pretty well covered.

COOPER: Richard, a lot is obviously riding on the radar provided by the Malaysians, Inmarsat used that data in calculations that helped them come up with the search off Australia, is that radar data something that should be re-examined?

QUEST: The radar data from the Malaysian military is pretty uncontroversial. It is blips showing the plane flying across the country and then going out west. But what it does show and I have on very good sources, it does not show it flying way points. It does not show some carefully constructed route west. It is a straight line west that happens to hit several way points.

Now, that takes us up to about 2:20 in the morning and that is the last known position. If the Inmarsat satellite handshakes fails on accuracy you're back to that position. You really are back to the very beginning of where the mystery begins. And once you're there, frankly, you are calling into question the corridors, you're calling into question the Inmarsat and ultimately the radar data.

COOPER: David Soucie, I talked to David Gallo about this a couple of days ago about the human aspect to the search, on the part of the search area, is there danger now with the disappointment that nothing has been found, that momentum for the search will somehow be lost?

SOUCIE: Well, I think just the energy level at this point regardless of whether they found or didn't find anything, there has to be times when you take breaks from this. Most of my investigations has been on land. I've seen the same thing on investigation teams. You just run out. You had some point you have to escape that because you start to draw incorrect conclusions. And the investigation can go quite awry if you don't take time to reorganize, to rethink and to get some sleep, get some food or bring some fresh eyes in to evaluate your own team to see are we on track or are we inventing something to go down the wrong path?

COOPER: David, you have been out there on the water on Air France flight 447, you know the disappointment and what it is like. Do you agree with David Soucie there?

GALLO: Yes, I agree with David completely on that. And they're going to get that break, Anderson, because one, the ship has been out there a long time. You know, after about four weeks at sea, you really do need to get into port and re-energize. But also, just to get a whole new set of tools to that area in Perth, is going to take some weeks. And then, they got to be interface with the ship. A plans have to be drawn up. So I think we're looking at least a couple of weeks of down time unless there is something out there that I don't know about. That will get out there on the site and go that deep. But I think it is going to be two or three weeks.

COOPER: Interesting, a lot more to cover tonight.

A quick reminder, first, make sure you can set your DVRs so you can always "360," never miss then whenever you like.

Next, some of the alternative theories that has sprung out in the last seven weeks and how they stand up to the evidence. Some of them of fantastic.

Later, the aviation mysteries, the remain mysteries even more than half a century later. Beyond Amelia Earhart, there is a lot more we don't know about.

(COMMERCIAL BREAK)

COOPER: The breaking news tonight, a U.S. Navy source telling us about what could be the next big move in the search for flight 370. A shift slightly to the north of the current six miles circle around where the second sonar was detected three weeks ago. So far, as you know, the current searchers come up empty.

Now, we talk a lot about how this absence of hard evidence, debris or sonar images. It doesn't necessarily mean anybody is doing anything wrong or that their strategy is somehow unsound. It does, however, create a vacuum which is being filled by any number of alternative theories, some are implausible than others, some of them just downright outrageous.

"360's" Randi Kaye investigate.

(BEGIN VIDEOTAPE)

RANDI KAYE, CNN CORRESPONDENT (voice-over): Conspiracy theorists believe they know what happened, even where the missing plane is. One of them were outlandish ideas, aliens stole flight 370 and abducted everyone on board. CASS SUNSTEIN, AUTHOR: The notion that a particular tragedy or the terrible thing that is happening is attributable to aliens, that seems preposterous.

KAYE: Cass Sunstein wrote a book about why conspiracy theories persists? He says people are drawn to mystery and suspicion, especially when feelings of fear, anger, and grief are involved, as is the case with the Malaysian airliner.

On social media, conspiracy theories about the missing plane are still going viral. This tweet pretty much covers it from time travel to an invisible cloak for the airplane. Others wonder was the plane hijacked to Afghanistan? Or did it land on the U.S. military base known as Diego Garcia? The island in the Indian Ocean has restricted security clearance.

But that has only amped up conspiracy theorists, so much so that it found its way into the White House briefing room.

UNIDENTIFIED MALE REPORTER: Some reports say that the flight could have landed in the U.S. military base, Diego Garcia, in the center of the Indian Ocean? Do you rule in that or rule out that?

JAY CARNEY, WHITE HOUSE PRESS SECRETARY: I'll rule that one out.

KAYE: Another conspiracy, an outrageous insurance scam. The Malaysian police chief gave that theory legs. Listen.

KHALID ABU KAKAR, MALAYSIAN POLICE CHIEF: Maybe somebody there on the flight that -- who bought huge sums of insurance who wants the family to gain from it? Or somebody who has so much money --

If not that, then perhaps some suggest North Korea took the airplane.

SUNSTEIN: The notion that North Korea would choose to exercise such authority and capacities as it has to hijack this plane, that seems in the realm of desperate speculation, too.

KAYE: Of course not all theories are as implausible as some of those. Others are more believable, pilot suicide has not been ruled out as well as rapid decompression, during which everyone on board passes out allowing the airplane to fly for hours until it runs out of fuel.

Another reasonable theory? Fire from lithium batteries in the cargo hold brought the plane down or a real hijacking that ended with the plane crashing into the sea.

SUNSTEIN: And so to exclude the ones that are wild and inconsistent with anything that is has happened in human history is probably a good start. And to have technological explanations that fed with sometimes happens or could happened, that is a little more solid.

KAYE: More solid, but still no concrete explanation and no plane.

Randi Kaye, CNN, New York.

(END VIDEOTAPE)

COOPER: Back now with Richard Quest and Jonathan Kay, we're hearing extensively about the line between solid theory and conspiracy theories. He is the author of among the truth hurts, journey to America's growing conspiracist underground."

Jonathan, it is really fascinating to me. These theories that persist around things that we find terrifying and certainly flying falls into that category.

JONATHAN KAY, AUTHOR: Sure, you know, even in normal times people are absolutely terrified in many cases about boarding an aircraft. Our brains tell us statistically it is quite safe, usually, to board an aircraft. But being 30,000 feet above the earth our imaginations go crazy, and we let our imaginations go wild. Sometimes we think about the people sitting around us. We think about terrorism. We think about all sorts of things. And it is only natural that this kind of human activity would be ripe fodder for conspiracy theorists.

COOPER: And Richard, I know, you have heard a lot of these conspiracy theories in twitter. People tweet them to you. They tweet them to me, as well. The fact though that authorities have at times not been forthcoming or as transparent as they could be in the investigation with information, certainly adds to these theories.

QUEST: I am not sure, I would go with that, Anderson, for the simple reason that the sort of conspiracy theories we're talking about come because there are not any facts to discuss. And so it is not as if -- the sort of issues that have not been revealed don't feed conspiracy theories.

I'll give you an example of just how wild this has all become. Yes, it is well known, the fact that I filmed with the first officer, Fariq Hamid in the cockpit about two weeks before MH 370. Pure unadulterated coincidence that the flight we filmed on has the same first officer. But there is no shortage of people out there. So they are suggesting CNN had something to do with it. CNN knows more about this, (INAUDIBLE), on and on it goes. So what I'm saying is, flying is such as Jonathan rightly points out, loss of control, therefore conspiracies will abound.

COOPER: Jonathan, I also find it interesting that some family members have latched on to some of these theories. Is that something you typically see in the wake of tragedies like this where again, they don't have an answer?

KAY: It is, and it happened after 9/11. You had all sorts of 9/11 conspiracy theories. One of the reasons for this is that anger and suspicions sometimes are easier emotions to control than sadness. If you're angry at someone, if you feel there is a political aspect to the emotion you're feeling at least you can direct that in an outward way. You can do something about it. You can agitate for something. Sometimes that is an easier emotion to manage than simply being sad because you lost a loved one.

COOPER: John, do you said that air travel would be a lot less mysterious and might be a fewer conspiracy theories that planes as attracted all times.

KAY: Well, one of the odd things about air travel is that pilots can turn off the transponders in the aircraft. That is one of the first things that the 9/11 hijackers did for instance, and one of the aspects of the current mystery about flight 370. One of the policy changes that might come out of this is that manufacturers may take away the ability for pilots to turn off transponders.

There actually really is no good reason why we shouldn't be able to track these aircraft at all times. So it would be interesting if that were, in my mind, the positive policy change that would come out of this incident.

COOPER: All right, Jonathan Kay, Richard Quest, thank you guys. For more on the story, you can go to CNN.com.

Coming up, what if flight 370 was never found? Hard to believe that could happen, but it would not be the first time in history that a plane has disappeared. Obviously, it goes beyond Amelia Earhart. We will take a look at other unsolved plane mysteries next.

Also ahead, an update from South Korea where the death toll continues to rise in the ferry disaster that's killed more than 180 people so far. The latest in the investigation coming up.

(COMMERCIAL BREAK)

COOPER: Once again, our breaking news tonight in the search for flight 370. A source in the U.S. Navy telling CNN that if no sign of the jet is found in the current search area, a new target will be in the north. And one of the enduring questions surrounding the mysteries how it passes a plane with 239 people on board could simply disappear.

And it seems like that would be impossible, turns out though, it is not unprecedented. There are other times in aviation history when planes disappeared, cases though remain unsolved to this day.

Kyung Lah reports.

(BEGIN VIDEOTAPE)

KYUNG LAH, CNN CORRESPONDENT (voice-over): Frustration mounts as the search continues for Malaysia airlines flight 370. But look back through aviation history and there are other mysteries that linger for months, years, even decades.

There have been planes in the past that have completely disappeared.

CAROL GRAY, AVIATION HISTORIAN: Certainly.

LAH: Carol Gray is an aviation historian. He says the most storied and enduring mystery is the disappearance of Amelia Earhart. She vanished in her twin-engine model plane over the Pacific Ocean in 1937 as she attempted to fly around the globe.

GRAY: There is still no concrete evidence as to what happened.

LAH: Her mystery unsolved.

For a passenger plane like that to disappear, that is not unprecedented either.

GRAY: No. And one it comes to mind is the British South American Airways.

LAH: Two British South American Airways jets under 51 passengers disappeared in the infamous Bermuda triangle in the 1940s. Also, that decade, five American bombers on the training mission vanished in the Bermuda. Even the search plane went missing all without a trace and still unsolved. Then there's this, the flying Tiger Line.

CARROLL GRAY, AVIATION HISTORIAN: It went off in 1952 near Guam, flying Tiger Line went off the radar, gone, disappeared.

LAH (on camera): No wreckage.

GRAY: No.

LAH (voice-over): It was 1962. A U.S. military flight with more than 90 people on board unsolved. The crash of Uruguay Air Force Flight 71 was so mysterious that Hollywood depicted the tale in the movie "Alive." In 1972, the 45 passengers crashed in the Andes Mountains. The survivors resorted to cannibalism to stay alive until they were found. This mystery solved after 72 days.

(on camera): What are historians and bloggers saying right now about this modern mystery?

GRAY: That this is a very weird event. A very strange event that doesn't lend itself to the normal sets of explanations.

LAH: As a historian, how gripping is this for you?

GRAY: It's phenomenally gripping. People are gripped by mysteries. Things that are unsolved just sort of grab people and especially when you have a common experience of flying.

LAH (voice-over): And that's why this historian says today's mystery must be solved.

GRAY: When you get on the plane the next time, are you going to wonder a little bit whether or not you're going to disappear? That's why it's so urgent that some satisfactory explanation happen fairly soon.

LAH: Kyung Lah, CNN, Los Angeles.

(END VIDEOTAPE)

ANDERSON COOPER, CNN HOST: The latest coming up on the investigation of the South Korea's ferry disaster, as the death toll continues to climb. Later, what's behind an alarming measles outbreak in the United States, I'll speak with Dr. Sanjay Gupta.

(COMMERCIAL BREAK)

COOPER: The death toll is rising from South Korea's ferry disaster as divers continue to recover bodies from the sunken vessel. A 187 people are confirmed dead, many of them high school students, 115 people still missing. President Obama arrived in Seoul today for the second stop in his week-long Asia visit. He said as a parent, he cannot begin to imagine what the families are going through. He gave South Korea's president an American flag along with his condolences.

(BEGIN VIDEO CLIP)

BARACK OBAMA, PRESIDENT OF THE UNITED STATES OF AMERICA: This flag was flown over the White House the same day as the sinking of the Sewol. And in that spirit I'm presenting this American flag to you and the people of the Republic of Korea on behalf of the American people. It reflects our deep condolences. But also our solidarity with you during this difficult time and our great pride in calling you an ally and a friend.

(END VIDEO CLIP)

COOPER: Now the ferry captain, 14 other crew members have been arrested as investigators try to piece together what happened to cause the disaster. Kyung Lah joins me now from South Korea with the latest. You're just outside the search area, what is the latest going on right now?

LAH: Well, as we speak, Anderson, divers are desperately trying to reach an area of the vessel, one room where they believe 50 girls may have huddled together as the waters were rising inside the vessel. They did find another room with 48 girls. They pulled those out. That is a second room where they believe there may be more girls. They're trying to access as much of this vessel as possible today because the weather is expected to turn in about 12 hours or so Korea time.

It will make it much more difficult. We're already hearing from divers that currents are cutting off their breathing tubes. They're in a mass of floating objects, so they're trying to get to as much of the ship as possible. Meanwhile, the search area being expanded, Anderson, because they are worried that bodies are drifting. They're asking fishermen to keep an eye out for anything that may be drifting -- Anderson.

COOPER: I'm just describing the room with all those young girls, just imagine what it is like for divers to come upon that in the darkness with low visibility. It just has to be so traumatic. Are authorities closer to find out in terms of the investigation what caused this to happen?

LAH: At this point, prosecutors have been very firm that this will take months to come to any sort of conclusion. A definitive conclusion. They are drilling down, though, on two very strong possibilities. That the cargo may not have been tied down properly and that some renovations made to the Sewol last year adding cabins to the upper part of the ship may have affected the balance and it may have been easier for the ship to have capsized. The government already responding, already considering legislation that would prevent vessels from being modified like this -- Anderson.

COOPER: I also understand there are some interesting -- shift of this vessel?

LAH: You're talking about a sister ship. The important thing to note here is that the sister ship is owned by the very same company. This gives you a picture of this company. In this sister ship there were a number of violations, safety violations that were fund by inspectors. There were 40 life rafts that didn't work. The emergency slides didn't work.

As far as tying down cars, because this is a ferry that did take cars back and forth, those ties didn't work. The containers, yes, they had ties but they did not work very well. So we're getting a picture into this company, Anderson, and whether or not safety was even on its map -- Anderson.

COOPER: Wow, Kyung Lah, I appreciate the update. Joining me now are cargo ship captain and maritime safety consultant, Jim Staples, Maritime Security Council Governor Emeritus Kim Petersen who is also the president of the Security Dynamics.

Captain Staples, you just heard from Kyung talking about major safety issues with the sister vessel. How big a concern are all those things she just mentioned, the emergency slide inoperable, equipment for tied down well, the ship not working well.

JAMES STAPLES, MARITIME SAFETY CONSULTANT: This is an amazing concern, Anderson, when you see that the sister ship is having problems with the safety, the life rafts and equipment we probably will most likely find that the same conditions existed on the Sewol. So we need to go back to find out if the company even bred a culture of safety with the management, a culture that operated within the two ships. So this is a ship that has primarily the same problems.

COOPER: And just as you said Captain Staples, the investigators are looking into whether or not cargo shifted on the ship. You have been a captain on this type of ship before. It is critical for every single piece of cargo to be latched down and latched down properly, correct? Explain why that is so critical.

STAPLES: Yes, Anderson, it is very critical. As we see, when a vessel takes a sharp turn or an easy turn, depending on what her stability is, we do not want that cargo to shift because what we have is a shift in the center of gravity, which can most likely move in an upward direction. This causes the vessel to become very top heavy in the rollover and not be able to come back to the stable condition. What we call it is a riding arm in the stability. And this is of great concern when there is a not very good riding arm. So making sure the cargo is latched is a priority on every vessel, from container ships to automobile carriers. This is one of the primary functions of the crew to make sure that everything is latched down. So this is of great concern along with the safety.

COOPER: And Kim, the modification that was made to the ship last year adding more passenger cabins, some say that that could have made it too top heavy. What do you make of that or would they make adjustments to any additions?

KIM PETERSEN, PRESIDENT, SECURITY DYNAMICS, LLC: Well, in fact, the organization that is responsible for that, before they would allow the additional cabin space to be built because it changed the metacentric height of the vessel, they stipulated that the owner of the Sewol would have to increase the amount of water ballast so that they could stabilize the vessel. And also they had to reduce the amount of cargos and containers. What they have to look into is whether or not the changes were ever made.

COOPER: Captain Staples, prosecutors I know have been conducting interviews with the crew members. They are finding out that the crew had not received standard safety training. As a captain is that just shocking to you? That would seem to be kind of the very basic thing that a crew should do.

STAPLE: Well, you said it right. It is a very basic thing. The basics of the basics. Training and safety is the prominent thing that we have to do on board ships. Everybody has to live in a safety culture to make sure we don't have these types of situations. So absolutely correct. It is astounding to me that in an environment like this, in a maritime country where they have a great ship-building capacity would even have people that don't train their people in safety. It just amazes me. I'm shocked and I'm surprised.

COOPER: Kim, I understand you have been in touch with some of the rescuers. I can't imagine, again, I come back to what it must be like for these divers working under these conditions, coming upon these kids, these children who have been in this ship now for more than a week.

PETERSEN: Anderson, it is absolutely horrific. And as more information is being revealed we're starting to see that there has been a fatal chain of predictable errors. We had failures in leadership, in training, in equipment. And now we're starting to look at design and government oversight. And that is why the investigators first began with the captain, next the crew. Then it was the company, then the owner.

And now we understand that the very agency that is responsible for oversight of the shipping industry has had its executives barred from travel out of the country because of what one investigator who was involved with the government said is a look at malpractice and potential corruption throughout the shipping industry in Korea. This is really shocking.

COOPER: Wow, it has gone further than this one vessel. Kim Petersen, I appreciate your time. James Staples as well.

Up next, the biggest surge in missiles in nearly 20 years has American health officials sounding the alarm. We'll take a look at what's behind the outbreak and what is being done to contain it.

Plus, new details tonight about what a 24-year-old American tourist allegedly did just before he was detained at customs in North Korea.

(COMMERCIAL BREAK)

COOPER: Tonight, U.S. health officials are warning about a disturbing surge in measles, 129 people have been affected in 13 states so far this year. That is the most in the first four months of any year since 1996. California is being hit hardest. Measles obviously is highly contagious and worldwide it's a leading cause of death in children.

It's also a disease that was virtually wiped out in this country in the United States more than a decade ago. Now it has a new foot hold. Stephanie Elam reports from the thick of the outbreak in California.

(BEGIN VIDEOTAPE)

UNIDENTIFIED MALE: This is a highly infectious disease.

STEPHANIE ELAM, CNN CORRESPONDENT (voice-over): It may start with a fever or a cough. But a splotchy red rash is its signature.

UNIDENTIFIED MALE: You're infected four days before you develop symptoms so you may not know you're sick.

ELAM: Many people in the United States have never seen measles since it has been gone over a decade ago.

ERIC G. HANDLER, MD., HEALTH OFFICER, ORANGE COUNTY HEALTH CARE AGENCY: I knew what to look for. The new physicians have not been used to it. So part of the public campaign is to make sure they know what to look for.

ELAM: In California, the number of confirmed cases has risen in the last couple of years, so far this year, 58, in Orange County, California, the number of cases has gone up.

HANDLER: We had 22 cases here in Orange County. That is a lot more than we normally have. We had over the past five years, no more than one or two cases a year.

ELAM: Why the sudden outburst? The number of parents refusing to vaccinate their children. Last year, in California, there was a 15 percent increase of people opting out of immunizations. In Orange County a 30 percent increase.

(on camera): Is there any reason to report that vaccinations could be dangerous to children? HANDLER: Absolutely not, there are serious consequences to having getting the measles.

ELAM (voice-over): So here, they're trying to spread the word faster than the virus that the vaccinations work.

HANDLER: The two immunizations, the MMR that you get is almost 95 to 98 percent protected.

ELAM: There have been no any new cases here in three weeks and more people are getting their shots. Maria Guardado tells me she brought her children in for their immunizations two days after hearing about the outbreak.

HANDLER: Education can overcome misperceptions.

ELAM: Another reason for the outbreak is our shrinking world. According to the Centers for Disease Control, 93 percent of the people diagnosed with measles in California contracted abroad or from someone who just returned from overseas.

HANDLER: Measles is pretty prevalent in other countries. So when go and visit, you need to make sure that you are immunized.

ELAM: Dr. Handler says the majority of people opting out of vaccinations are in the more affluent parts of Orange County, but he hopes through education their minds will be changed. Stephanie Elam, CNN, Orange County, California.

(END VIDEOTAPE)

COOPER: Again, until recently, U.S. health officials counted measles as a disease. It wiped out in this country and now it is back. I want to bring in chief medical correspondent, Dr. Sanjay Gupta. Sanjay, more people in the U.S. had been infected with measles during the first four months this year than in the past 18 years, why the increase?

DR. SANJAY GUPTA, CNN CHIEF MEDICAL CORRESPONDENT: You know, I think there are two things happening here. As you know, Anderson, I just returned from Africa covering this Ebola story. And one of the things it reminds you are, we live in a very global world where these pathogens can move around the world faster than ever before. And what is happening, much of these cases in the United States came from overseas initially.

Seventeen of the cases, for example, from the Philippines. But the other thing here is, something we talked about a lot is that you have increasingly these pockets of people not getting vaccinated. And that is a real problem, it is a very contagious disease. And if somebody comes from another country it could spread very quickly in these pockets.

COOPER: You're a doctor, have you seen the spread of measles?

GUPTA: You and I have seen the spread of measles but it was in Africa. Back when we worked on the documentary years ago, as a doctor in the United States I have not seen a patient with measles. We have made really good progress. But in other cases you still see cases. In fact, take a look at the map. Anderson, you can get an idea of what it looks like around the world. Those places where you see the highest number of cases, the most cases, they are not surprisingly the places where the vaccinations are the lowest.

COOPER: And some of the symptoms, what should people look for, I mean, how dangerous are we talking about?

GUPTA: It starts off in many ways as a viral illness. People get the fatigue, the headache. The muscle aches, what is characteristic of the measles, you get this characteristic rash around your body. This sort of almost pinpoint rash. It can also arriving your eyes. Those are some of the outward symptoms. Where it can get really scary and out of control is where you develop infections of the lung and brain. And even for people who recover after an infection of the lungs and brain it can be debilitating. Their lives are just never the same.

COOPER: If you get the vaccinated as a child, it is effective?

GUPTA: Adults that got a shot after 1956, it may be worthwhile to make sure you're still immunized. They can do a blood test to determine that. But if you look at childhood vaccination programs just over the last 20 years they have prevented some 300 million illnesses in this country, 300 million. Close to a million deaths prevented. We talk so much about the fact that we treat disease after it occurs. Everybody gives a lot of lip speak to prevention, they have the data to show that.

COOPER: It also saved billion of dollars in health care costs. Bottom line, you get your kids the vaccine, there is no reason not to vaccinate your kids.

GUPTA: Yes, I'm glad you asked that. There is no reason to equivocate on this. You hear people say yes, I do this. I got my kids vaccinated. I have three young children, eight, six, and four. I said that because I read all the studies. I've looked at the studies, you and I interviewed Dr. Wakefield together who wrote this paper that caused the controversy. He was subsequently dismissed. With all that I know and all I researched, yes, I chose to do it with my own children. I believe there is something important about that.

COOPER: All right, Dr. Sanjay Gupta. Sanjay, thanks.

And new information about the 24-year-old American tourist detained by North Korea as he was entering the country.

(COMMERCIAL BREAK)

COOPER: Let's get caught up on some of the other stories we are following. Susan Hendricks has a 360 bulletin -- Susan.

SUSAN HENDRICKS, CNN CORRESPONDENT: Anderson, new details about the 24-year-old American tourist detained by North Korea and concern at the State Department. (BEGIN VIDEO CLIP)

JEN PSAKI, STATE DEPARTMENT SPOKESPERSON: We are of course aware of the reports that a U.S. citizen was detained in North Korea. As you all know, there is no greater priority to us than the welfare and safety of U.S. citizens. We don't have additional information to share at this time. We have been in touch with the Embassy of Sweden about these reports, as you know, Sweden is our protecting power in North Korea.

(END VIDEO CLIP)

HENDRICKS: A western diplomat tells CNN the young man identified by North Korea as Miller Matthew Todd tore up his visa as he was entering the country and reportedly was acting strangely. The diplomat said according to witness accounts he appeared to go with the North Koreans willingly.

And updated charges against a teen accused of stabbing 20 students and one adult at a Pittsburgh high school. The 16-year-old is now charged with 21 counts of attempted homicide. Two survivors are in stable condition, the other in fair condition.

The mother of the Somali-American teenager who stowed away in the wheel of the 767 said he wanted to return to Africa after learning she was alive. That's according to "Voice of America" news. The woman told the news service her former husband had told their son she was dead. The boy ended up in Maui, Hawaii.

And the private company says they want more business with the military even if it means going to court to get it. The founder says that they will sue the air force to challenge a multi-billion dollar contract with the competing company. No comment from the air force. They are behind the company that makes tesla electric cars -- Anderson.

COOPER: Susan, thanks very much. That does it for us. "CNN TONIGHT" starts now.